DE3713997A1 - FLUID CYLINDER - Google Patents

Description

The present invention relates to a fluid cylinder, which has a pneumatic cylinder and a hydraulic cylinder includes linder.

When various moving parts are mechanically operated will generally use a motion control system a pneumatic cylinder or a hydraulic cylinder ver turns, these cylinder mechanisms also act as buffers unit used when the movable elements be stopped.

In such a mechanism with a pneumatic cylinder is the medium used to control movement Air, so that the entire device mainly one Air cylinder, a switching valve and a control system around sums up. This device can therefore be created inexpensively will; since it is a compressible air Fluid acts is the responsiveness of the mechanism when the moving parts are stopped, often by just moderate reliability.

In order to overcome these disadvantages, mechani brake device provided a piston rod. The This piston rod moves with it when it stops an average braking stroke during a certain time pe period in a current braking state, so that the moving baren elements beyond the predetermined stopping position leak and the positioning accuracy of the movable Elements is not achieved.

The above-mentioned mechanical braking device has further disadvantages, such as a small stop power, low reliability, wear on the brake  due to repeated use for a long time, resulting in a Worsening of the braking properties results.

Since the ver with the oil-hydraulic cylinder mechanism applied pressure medium (oil) is incompressible and the col Movement stops immediately when the supply of high pressure oil is stopped in the cylinder is the positioning accuracy of the control system good. Because of the incompressible Print media can have a higher performance and a larger one Holding force can be provided. But since Ölhy Draulic units are generally expensive and space-consuming are, it is difficult to find an inexpensive and space-saving Find unity.

To the disadvantages of the cylinder mechanisms mentioned above a combination of two cylinders units in tandem or connected in parallel to one moving part on the one hand by a pneumatic To drive pressure and secondly by a hydraulic brake pressure, the position of the movable Part by a in the oil line of the oil-hydraulic Sy stems arranged stop valve is controlled.

Because with such a mechanism the moving part moved by a pneumatic system and by an oil hy drastic system is stopped, the facility can compared to the case that the entire system is oil-hygienic draulic basis, be inexpensive. The positioning accuracy of the moving part can by the control by means of oil hydraulics who improved the. The facility also meets the demands of the host economy and operating conditions since the stop valve in the oil line of the oil hydraulic system as a control tion of the movable part is provided and only ge needs to be opened or closed.

As several independent cylinder units in tandem  voltage or parallel to each other and with each other connected, the longitudinal dimension or the lateral dimensions due to the multiple cylinder units ten. This construction is therefore in terms of their Compactness and size could be improved.

In addition, there is no interchangeability in the pouf device when the moving part is stopped.

It is therefore an object of the invention to provide a fluid cylinder to create, which overcomes the disadvantages mentioned above and a high positioning accuracy is sufficient, a high Has holding power, inexpensive and small in size is to act as a control system for a moving part NEN and as a buffer when stopping a be moving part can be used.

This object is achieved by a Fluid cylinder with a pneumatic cylinder mechanism mus, an oil hydraulic brake cylinder mechanism that concentric with the pneumatic cylinder mechanism is connected to an oil line connected to the front cam mer and the rear chamber of the oil hydraulic cylinder mechanism is connected and with a control nerve til that is in the oil line to control the oil flow is arranged.

In the following, execution is based on a drawing examples of the invention described in more detail. Show it:

Fig. 1 in a sectional view a first execution form of a fluid cylinder according to the invention,

Fig. 2 is an enlarged sectional view of a variant of an oil hydraulic piston of a fluid cylinder according to the invention,

Fig. 3 is a sectional view of a second execution form of a fluid cylinder according to the invention,

Fig. 4 is a sectional view of a third embodiment of a fluid cylinder according to the invention and

Fig. 5 is a sectional view of a fourth embodiment of a fluid cylinder according to the invention.

Fig. 1 shows a control system for moving a movable part be according to a first embodiment of a hydraulic compound cylinder according to the invention.

The fluid cylinder in Fig. 1 has a hollow piston rod 1 , which is also used as an inner cylinder 2 , a piston 3 , which is provided at the outer end of the piston rod 1 , and an outer cylinder 4 , the one in its axial center Has hollow rod 5 . The inner cylinder 2 and the hollow rod 5 or the Kol ben 3 and the outer cylinder 4 fit well together and are slidably connected to each other.

The inner volume, which varies due to the relative movement of the inner cylinder 2 and the hollow rod 5 , forms a rear, oil-hydraulic chamber 6 in the associated structure of the inner cylinder 2 and the hollow rod 5 .

The two cylinder chambers, the volume of which varies in the outer cylinder 4 by moving the piston 3 , form a front, oil-hydraulic chamber 7 on one side and a pneumatic chamber 8 on the other side. The rear chamber 6 of the inner cylinder 2 is connected to the front of the chamber 7 of the outer cylinder 4 through an oil line 11 with a control valve 9 and an oil chamber 10 in connection.

In Fig. 1 it can be seen that the oil line 11 is put together from a hollow portion 12 d of the above-described hollow rod 5 , a line 13 formed in the cylinder wall of the outer cylinder 4 and lines 14 a and 14 b gene, the are arranged between the control valves 9 and the hollow section 12 of the hollow rod 5 or between the control valve 9 and the line 13 through the oil chamber 10 . The arranged between the lines 14 a and 14 b control valve 9 is formed, for example, as an electromagnetic stop valve. The variable volume chamber 10 comprises a to be pressurized plate 10 a disposed inside the chamber 10, and a spring 10 b, which is biased a and an end wall of the oil chamber 10 between one side of the pressure plate 10 is arranged, to pressurize the oil present in the chamber 10 by pressing on the plate 10 a .

Via a line 16 with the pneumatic chamber 8 of the outer cylinder 4, a pneumatic unit 15 is connected, which has a compressor, a pressure control tank, a switching valve and a controller.

In the front oil-hydraulic chamber 7 of the outer cylinder 4 Zy a helical compression spring 17 is arranged in order to be able to move the piston rod 1 with the piston 3 back and forth ben.

Air-tight or liquid-tight sealing elements 18 are attached between the holding rod 5 and the inner cylinder 2 or between the piston 3 and the outer cylinder 4 and also between the piston rod 1 and the outer cylinder 4 .

The first embodiment shown in FIG. 1 is a single-acting fluid cylinder, wherein the hollow piston rod 1 , which is also used as an inner cylinder 2 , acts as an output rod and is coupled to a movable unit 19 directly or via transmission devices.

The movable unit 19 can be any movable part, for example a movable table of a machine tool, a scanner for a sensor, a trough for a storage rack or a switching element of a mechanical switching device.

In the embodiment in Fig. 1, the movable unit 19 is moved, the control valve 9 of the Lei device 11 is opened to establish the connection between the rear oil-hydraulic chamber 6 of the inner cylinder 2 and the front oil-hydraulic chamber 7 of the outer cylinder 4 . From the verbun with the pneumatic unit 15 which line 16 is compressed air in the Pneumatikkam mer 8 of the outer cylinder 4 is introduced.

When the high pressure air is introduced into the pneumatic chamber 8 , the piston rod 1 moves out of the outer cylinder 4 to transmit the movement of the piston rod 1 to the movable unit 19 and thus the movable unit 19 in to move a predetermined direction.

In this case, the inner volume of the front oil hydraulic chamber 7 decreases by the relative movement of the piston 3 and the outer cylinder 4 , while the inner volume of the rear oil hydraulic chamber 6 increases by the relative movement between the inner cylinder 2 and the hollow rod 5 . The oil in the front oil-hydraulic chamber's 7 thus flows via the oil line 11 into the rear oil-hydraulic chamber 6 .

The rear chamber 6 of the inner cylinder 2 and the front chamber 7 of the outer cylinder 4 are constructed so that the respective volume decrease or increase in the rear and front chambers 6 and 7 are the same.

The oil thus flows easily from the front chamber 7 into the rear chamber 6 . However, if the two chambers differ in volume, for example due to manufacturing tolerances, the oil chamber 10, which is variable in volume, can compensate for these volume differences.

When the movable unit 19 in its desired position within the effective stroke of the fluid cylinder is halted, the control valve 9 in the oil line 11 is closed to the oil flow between the front oil-hydraulic chamber 7 and the rear oil-hydraulic chamber 6 of the outer cylinder 4th to prevent.

In this case, since the flow of an incompressible fluid (oil) is prevented in the front and in the rear chambers 7 and 6 , the piston rod 1 will not move even if compressed air is further introduced into the pneumatic chamber 8 . Accordingly, when the Ven valve 9 is closed, the movable unit 19 stops at the same time to control the position of the movable unit 19 .

If the line 16 is connected to the atmosphere by opening the switching valve, the piston rod 1 with the piston 3 will be pushed back into the outer cylinder 4 by the helical compression spring 17 .

The embodiment according to FIG. 1, for the following modifications may be used.

The hollow rod 5 can be formed, for example, as a hollow piston connected to a hollow piston rod.

The control valve 9 can be used as a stop valve, as a throttle valve or as a single valve with stop and throttle properties.

The line 14 b of the oil-hydraulic system can also be arranged as indicated by the dashed line between the oil chamber 10 and the front chamber 7 of the outer cylinder 4 , or as indicated by the dashed line in FIG. 1 as a dashed line is indicated, between the oil chamber 10 and the end of the front chamber 7 .

As shown by a dashed line in FIG. 4, the line 14 b is passed through the piston 3 , so that the line 14 b in the penetrating section of the line 14 b is displaceable to between the piston 3rd air-tight and liquid-tight, so that the line 13 of the outer cylinder 4 can be wegge.

The oil chamber 10 can be formed in the oil line 11 or in one piece with the piston 3 , as shown in FIG. 2.

The chambers 6 , 7 and 8 of the inner and outer cylinders 2 and 4 can be designed so that the chambers 7 and 8 are designed as an oil-hydraulic front and rear chamber and the chamber 6 as a pneumatic chamber. In this case, the oil line 11 is arranged with a control valve 9 and an oil chamber 10 between the chambers 7 and 8 , while the line 16 of the pneumatic unit 15 is connected to the chamber 6 .

When the piston rod 1 is fixed in place, the outer cylinder 4 becomes the movable power side.

The front and rear oil hydraulic chambers are designed so that the volume change between the two, as described above, is the same, so that with a high positioning accuracy, as in this case, the oil chamber 10 can be omitted.

The second exemplary embodiment of a hydraulic connecting cylinder according to the invention is described below with reference to FIG. 3.

The second embodiment of the invention is a hy draulic compound cylinder for buffering a movable unit and has substantially the same structure as the first embodiment shown in FIG. 1, except that the control valve of the oil line 11 between the rear hydraulic chamber 6 and front oil hydraulic chamber 7 is designed as a throttle valve, the open chamber 8 a is opened via an opening 20 connected to the atmosphere and that the helical compression spring 17 is omitted.

The pneumatic system is not loaded and only includes the open chamber 8 a .

In the second embodiment according to FIG. 3, the piston rod 1 arranged corresponding to the stopping position of the movable unit 19 is pulled out of the outer cylinder 4 . When the movable unit 19 has reached the stopping position, it collides with the piston rod 1 .

In this case, the piston rod 1 is inserted by the movable unit 19 into the outer cylinder 4 , where the volume in the rear hydraulic chamber 6 decreases due to the relative movement of the inner cylinder 2 and the hollow rod 5 and the volume in the front oil hydraulic Chamber 7 increases by the relative movement of the Kol bens 3 and the outer cylinder 4 . The oil in the rear chamber 6 thus flows into the front chamber 7 via the oil line 11 .

Here, the oil flowing through the oil line 11 is throttled by the control valve 9 equipped with a throttle valve on its way from the rear chamber 6 to the front chamber 7 , whereby the movable unit 19 in contact with the piston rod 1 is gently braked.

In this way, the movable unit 19 is stopped while the shock is cushioned in the transition from the moving state to the stopping state.

In the above described second embodiment, the piston 3 comprehensive piston rod 1 may comprise a Schrau bendruckfeder 17, which is disposed in the open chamber 8 a. The piston rod 1 can also be pushed out that air is pumped into the open chamber 8 a of the outer cylinder 4 .

In addition, the second embodiment of the inven be modified in the same way as the first Embodiment.

With reference to Fig. 4, a third embodiment of an inventive hydraulic Verbundzy cylinder is described.

The third embodiment includes motion control system for a movable unit, which is similar Way like that of the first and second embodiments le, is built. However, it is the third Embodiment around a double-acting Fluidzy lighter.

The third exemplary embodiment shown in FIG. 4 has a hollow rod 21 , a first hollow piston rod 22 , which also acts as a first cylinder 23 , a first piston 24 , which is attached to one end of the first piston rod 22 , a second hollow piston rod 25 , which also acts as a second cylinder 26 , a third hollow piston rod 27 , which also acts as a third cylinder 28 , a second piston 29 , the rod 27 is provided at one end of the third piston, and a fourth cylinder 30th

The hollow rod 21 , the second piston rod 25 and the fourth cylinder 30 of these components of the third exemplary embodiment are integrated into one another in a concentric arrangement such that the hollow rod 21 is arranged in the middle, the second piston rod 25 outside around the hollow rod 21 and the fourth Cylinder 30 around the outside of the piston rod 25 .

The first piston rod 22 and the third piston rod 27 are also integrated with one another in a concentric arrangement, so that the first piston rod 22 is arranged on the inside and the third piston rod 27 is arranged on the outside.

In addition, each of the hollow rod 21 and he ste cylinder 23 , the first piston 24 and the second cylinder 26 , the second cylinder 26 and the third cylinder 28 , the second piston 29 and the fourth cylinder 30 fit exactly into one another and in sealing Way arranged against each other.

In the arrangement described above, the first cylinder 23 changes its volume due to its relative movement with the hollow rod 21 to form a rear oil-hydraulic chamber 31 .

The second cylinder 26 varies its chamber volume on both sides by its relative movement with the first piston 24 such that the first side forms a front oil-hydraulic chamber 32 and that the other side forms an open chamber 34 which has an opening 33 with the atmosphere connected is.

The third cylinder 28 varies its chamber volume through its relative movement with the second piston rod 25 to form an open chamber 35 , which communicates with the atmosphere via an opening 36 .

The fourth cylinder 30 varies its chamber volume on both sides by a relative movement with the second piston 29 such that one side forms a rear pneumatic chamber 37 and the other side forms a front pneumatic chamber 38 .

The rear oil-hydraulic chamber 31 and the front oil-hydraulic chamber 32 are connected to one another via an oil line 40 having a control valve 39 .

The line 40 shown in FIG. 4 comprises a hollow section 41 of the hollow rod 21 , a line 42 passing through the cylinder wall of the second cylinder 26 , lines 43 a and 43 b , which between the hollow section 41 and the line 42 in the in the kind shown Fig. 4 are arranged, and a control valve 39. The control valve 39 may be formed as between the lines 43 a and 43 b vorgese Henes electromagnetic stop valve, for example.

Via the lines 45 a and 45 b with the rear pneumatic chamber 37 or with the front pneumatic chamber 38, a pneumatic unit with a compressor, a pressure control tank, a switching valve and a control tion.

The seals 81 shown in FIG. 4 and the movable unit 19 are constructed in the same way as in the previously described exemplary embodiments.

In the third embodiment shown in FIG. 4, the movable unit 19 is moved, the control valve (stop valve) 39 of the oil line 40 is opened to establish a connection between the rear chamber 31 and the front chamber 32 . Through the unit connected to the Pneumatikein 44 line 45 a pressurized compressed air is passed into the rear pneumatic chamber 37 .

When the compressed air is passed into the rear pneumatic chamber 37 , the third piston rod 27 is pushed out of the fourth cylinder 30 by the second piston 29 under the effect of the air pressure. The coupled with the third piston rod 27 first piston rod 22 is pushed out of the second cylinder 26 accordingly. These push-out movements of the piston rod are transmitted to the movable unit 19 in order to cause its movement in a predetermined direction.

As the volume in the front chamber 32 decreases, the volume in the rear chamber 31 increases simultaneously. Thus, the oil flows from the front chamber 32 via the oil line 40 into the rear chamber 31 , as already described above.

Then, when the moving unit 19 in motion is stopped at a desired position within the effective stroke, the control valve 39 of the oil pipe 40 is closed to break the oil pipe 40 between the rear chamber 31 and the front chamber 32 under. Since the flow of the incompressible fluid (oil) is thus stopped both in the chamber 31 and in the chamber 32 , the piston rods can no longer move, as was already described in the first exemplary embodiments. The movable unit 19 accordingly stops at the same time when the control valve 39 is closed ge.

In order to move the movable unit 19 in the opposite direction to that described above, compressed air is introduced into the front chamber 38 to push the piston rods into the respective cylinders. In this case, if the control valve 39 of the oil line 40 is closed in order to interrupt the oil flow between the rear chamber 31 and the front chamber 32 , the movable unit 19 stops again in a predetermined position.

The following are modifications of the fourth embodiment Example described.

In Fig. 4, a plurality of cylinder chambers, that is, front chambers are provided, the volume of which decreases when the piston rods are pushed out of the respective cylinders, and a plurality of cylinder chambers, ie, rear chambers, the volume of which decreases when the piston rods are pushed into the respective cylinders and any set of the front and rear chambers can be used as the front and rear oil hydraulic chambers or as the front and rear pneumatic chambers.

More specifically, the arrangement can be arbitrary selected set of front and rear chambers for the oil hydraulic system are used and another arbitrary set of front and rear chambers for the pneumatic system. The lines of the oil hydraulic Systems are with the front and rear oil hydraulics chambers connected while the lines of the pneu matic system with the front and rear pneumati chambers are connected. The remaining front ones and rear chambers are connected to the atmosphere dung.

The above-described front and rear oil-hydraulic chambers are preferably constructed so that their respective volume increase and decrease are the same. However, if their volume exchange is not the same, an oil chamber can be provided in the oil line or, as shown in FIG. 2, in an oil-hydraulic piston.

The control valve 29 is composed of a stop valve and a throttle valve. It can also be a single valve that includes a throttle and shutdown function.

The line 43 b of the oil-hydraulic system can be arranged as shown by the broken line in Fig. 4. In this case, the line 42 penetrating the cylinder wall 42 of the second cylinder 25 can be omitted.

When the piston rods are fixed, the cylinders to the extension side.

In the following, a fourth exemplary embodiment of a hydraulic composite cylinder according to the invention is described with reference to FIG. 5. The fourth embodiment is used for a motion control system of a movable unit and is substantially the same as the double-acting cylinder acc. Fig. 4 constructed.

Therefore, only the differences of the fourth exemplary embodiment from the third exemplary embodiment will be shown. Fig. 4 described.

In Fig. 5, a second cylinder 26 is fixedly connected to both end faces of the fourth cylinder 30 .

A third piston rod 27 a is constructed from a plurality of piston rods and differs from the cylindrical shape described above. A first piston rod 22 is connected via a plate-like coupling 26 , for example a pull plate shown in FIG. 5, to the piston rods 27 a .

For this reason, the third cylinder 28 and the open chamber 35 of the third embodiment shown in FIG. 4 are not provided in the fourth embodiment in FIG. 5.

One of the two lines 43 a and 43 b , namely the Lei device 43 b , the oil line 40 is arranged as shown by the broken line with colons in Fig. 5. In the case of the solid line, the line 43 b is connected to an opening 47 .

If an opening, not shown, which communicates with a rear hydraulic chamber 31 , the left-hand end of a first piston rod 22 passes through, the line 43 a can be connected to this opening. In this case, the hollow rod 21 can be formed as a normal rod without a hollow section 41 .

In addition, the modifications described with reference to FIGS. 1 to 4 can also be performed in the fourth exemplary embodiment. Fig be provided. 5,.

The movable unit 19 is moved in the exemplary embodiment shown here by a pneumatic system, while the control of the positioning of the movable unit is performed by an oil-hydraulic system. The operation of the exemplary embodiment shown here is essentially the same as in the third exemplary embodiment shown in FIG. 4, so that the detailed description is omitted here.

In the first, the second and the third embodiment, for example. Figs. 1, 3 and 4, the line 13 of the outer cylinder 4 and the line 42 of the second piston rod 25, which also acts as a second cylinder 26, in the case where the outer cylinder 4 and the second Col benstange are double-walled 25 , Be formed out so that they take advantage of the inner gap of the double wall construction. In this case, the inner gap can be connected to the front chamber 7 and the line 14 b ( FIGS. 1 and 3) or to the front oil-hydraulic chamber 32 and the line 43 b ( FIG. 4), in which in the inner wall of the double wall used as lines 14 b and 43 b, one or more openings are provided.

As described above, the hy according to the invention comprises draulic compound cylinder a pneumatic cylinder mechanism, an oil hydraulic Brake cylinder mechanism that is concentric with the tire matic cylinder mechanism is connected, an oil line device for connecting the front chamber and the rear Chamber of the oil hydraulic oil cylinder mechanism and a provided in the oil line for controlling the oil flow Control valve. The hydraulic compound cylinder can therefore like a pneumatic cylinder mechanism as simple acting, double-acting and passive cylinder be det. The compound cylinder can be used for a control system for moving a movable unit to stop them at a predetermined position or around when stopping the movable unit as a shock absorber Act. In this case, the accuracy of the oil hydraulic system can be increased while the host Efficiency achieved through the pneumatic system becomes. The pneumatic cylinder mechanism and the oil hy draulic cylinder mechanisms are concentric order connected to each other by a large length to avoid stretching and a large width, as with existing double-acting cylinders is available. In this way, the construction volume of the hydraulic  Compound cylinder reduced.

Claims (5)

1. Fluid cylinder, characterized by a pneumatic cylinder's mechanism ( 3 , 4 , 8 , 15 , 16 ), an oil-hydraulic brake cylinder mechanism ( 1 , 2 , 3 , 4 , 5 , 6 , 7 ), which with the pneumatic cylinder mechanism in con centric Arrangement is connected, an oil line ( 14 a , 14 b ) for connecting the front chamber ( 7 ) and the rear chamber ( 6 ) of the oil-hydraulic cylinder mechanism and a control valve ( 9 ) which for controlling the oil flow in the oil line ( 14 a , 14 b ) is provided. 2. Fluid cylinder according to claim 1, characterized in that the pneumatic cylinder mechanism is single-acting ( 3, 8 ), double-acting ( 37, 38 ) or as a passive cylinder mechanism ( 3 , 8 a ) is formed. 3. Fluid cylinder according to claim 1 or 3, characterized in that the control valve ( 9 ) contains at least one throttle valve and a stop valve. 4. Fluid cylinder according to at least one of claims 1 to 3, characterized in that an oil chamber ( 10 ) is provided in the oil line ( 14 a , 14 b ). 5. Fluid cylinder according to at least one of claims 1 to 4, characterized in that an oil chamber ( 10 ) is provided in a piston ( 3 ) of the oil-hydraulic system.